Evaporator coil construction



Jan. 9, 1968 KLOSTER ET AL 3,362,187

EVAPORATOR COIL CONSTRUCTION Filed March 9, 1966 2 Sheets-Sheet 1 VENTORS I GORDON A.[L0-STER 50 F I 2 ARTHUR G LARSON BY avy A 7- TOR/V5 Y5 Jan. ,9, 1968 G. A. KLOSTER ET AL 3,362,187

EVAPORATOR COIL CONSTRUCTION Filed March 9, 1966 2 Sheets-Sheet 2 INVENTORS GORDON A.KL 5TER ARTHUR G. LARSON ATTORNEKS United States Patent 3,362,187 EVAPORATOR COIL CONSTRUCTION Gordon A. Kloster, Minneapolis, and Arthur G. Larson, Mound, Minn., assignors to McQuay, Inc., Minneapolis, Minn., a corporation of Minnesota Filed Mar. 9, 1966. Ser. No. 533,064 3 Claims. (Cl. 62347) This invention pertains to evaporator coil constructions used with ice makers, and more particularly to an evaporator coil used in conjunction with a spot freezing type of ice maker wherein water is caused to flow over a refrigerated spot to cause ice to freeze thereon and to grow to a desired size and shape.

A spot freezing ice maker of the type generally involved in the present invention is disclosed in US. Patent Muffly 2,774,223, and generally comprises a pair of metal surfaces arranged to face each other. Directly opposed areas or spots of the metal surfaces are cooled by means of metal buttons which are soldered, or otherwise suitably connected, to the outside of the metal surfaces in directly aligned pairs. The buttons are in turn soldered to an evaporator tube which carries a liquid refrigerant and which supplies the cooling effect to the buttons and in turn to the spots on the metal surfaces. Water is caused to flow over the inside of the metal surfaces and freezes on the refrigerated spots of the surfaces. The freezing continues until the ice formed on the two opposed spots grows large enough that the two pieces of ice join together thereby forming a generally spool-shaped ice particle.

This prior art ice maker has a disadvantage in that the buttons which are soldered to the metal surfaces and the evaporator coils are relatively thick, and therefore have a decreased heat transfer characteristic, which results in a decrease in ice maker efiiciency. In addition, the solder which connects the buttons to the evaporator coil, and

also connects the buttons to the metal surfaces, has a very poor heat transfer characteristic, and therefore tends to insulate the buttons from the evaporator coil, and also from the metal surfaces, thereby greatly reducing the ice maker efliciency.

The present invention pertains to an improved evaporator coil for use in the above-described type of spot freezing ice maker; the improved evaporator coil comprising a metal tube having a generally rectangular cross section, so that the opposed side walls of the tube are generally flat, the metal tube having the wall portions formed to provide a plurality of raised buttons which are spaced along the metal tube in the direction of its longitudinal axis. The raised buttons of the evaporator tube are then soldered or otherwise suitably connected so that they contact the fiat metal surfaces, so as to refrigerate isolated spots on the metal surfaces. Since the wall thickness of the improved evaporator coil is relatively thin, this coil has a much better heat transfer characteristic than prior art devices, and in addition, only one soldering joint is required, namely between the raised button of the evaporator coil and the metal surface. This also increases the heat transfer characteristic of the evaporator metal surface junction, and increases the efficiency of the ice maker.

It is one object of this invention, therefore, to provide an improved ice maker.

It is another object of this invention to provide an ice maker having an improved evaporator coil.

A further object of this invention is to provide an evaporator coil wherein the walls thereof are formed to provide a plurality of raised buttons.

These and other objects of our invention will become apparent to those skilled in the art upon consideration of the accompanying specification, claims, and drawings.

dicate like parts throughout the several views:

FIG. 1 is a diagrammatical representation of an ice maker of the present invention, some parts thereof shown in section;

FIG. 2 is a sectional view taken along the line 2--2 of FIG. 1, some parts thereof removed;

FIG. 3 is an enlarged sectional view taken along the line 33 of FIG. 1;

FIG. 4 is a perspective view of an evaporator coil made in accordance with the present invention; and

FIG. 5 is an enlarged top plan view of a portion of the evaporator coil of FIG. 4, parts thereof being broken away and shown in section.

Referring to the drawings, there is shown a compressor having an output 11 and an input 12. The output 11 of compressor 10 is connected by means of a pipe 13 to a T connector 14, having one of its outputs connected by means of a pipe 15 to the input of a condensor 16. The output of condenser 16 is connected through a dryer 17 and a strainer 20 to one end of a capillary tube 21. The other end of the capillary tube 21 is connected to the input of an evaporator 22. Evaporator 22 comprises a plurality of evaporator coils 23. The output of evaporator 22 is connected to the input of an accumulator 24. The output of accumulator 24 is connected by means of a pipe 25 to the input 12 of compressor 10. The other output of T connector 14 is connected through a hot gas solenoid 26 to the input of the evaporator 22.

Evaporator 22 is constructed from a plurality of evaporator coils 23 each of which comprise a metal tube having opposed, generally flat, Walls 30 and 31, and opposed, generally fiat, walls 32 and 33, the walls 30, 31, 32 and 33 forming a generally rectangular shaped metal tube in cross section. The opposed walls 30 and 31 are formed to provide a plurality of raised buttons which are spaced along the metal tube in the direction of the tubes longitudinal axis.

Wall 30 of coil 23 is formed so that a first wall portion 34, and each successive odd numbered wall portion, for example, 35 and 37, is offset in one direction, while wall 31 has a second portion 40, and each successive even numbered portion, for example, 42 and 44, offset in an opposite direction.

Evaporator coil 23 can be formed from any suitable metallic material, such as copper tubing, and forming the raised buttons of the coils by means of a die. Preferably, in forming the raised buttons the copper tubing is filled with an incompressible liquid, such as water, with a relief valve provided to release the hydraulic static pressure before the bursting pressure of the copper tube is reached. The water filled coil is inserted in the suitable die and the die halves are forced together thereby deforming the walls of the copper tubing. As the walls of the copper tube are deformed, a hydraulic static pressure builds up within the copper tubing which forces the tubing walls to correspond to the cavities of the die.

A metal surface 45, for example, a stainless steel plate, is in contact with the raised buttons on the wall 30 of each of the evaporator coils 23, and a metallic surface, for example, stainless steel plate 46, is in contact with the raised buttons of the wall portion 31 of each of the evaporator coils 23. The metal surfaces 45 and 46 are connected to the raised buttons in any suitable manner, such as soldering or brazing.

The water circuit for the ice maker of the present invention is as follows: :a water inlet 50 is connected by means of a pipe 51 to a float valve 52. The float valve 52 controls the level of water in a water pan 53. A pump 54 has an outlet connected by means of a pipe 55 to a water header 56. A water distributor 57 is mounted below the water header 56, and has a plurality of apertures 58 in the bottom thereof, the apertures 58 being arranged of rows above the metal surfaces 45 and 46. Water battles 60 are mounted below the apertures 58 of the water distributor 57 and direct water from the distributor over the faces of the metal surfaces 45 and 46. Below the metal surfaces 45 and 46, and above the water pan 53, is mounted an inclined screen 61. One end of screen 61 overhangs an ice storage bin 62.

The refrigerant circuit of the ice maker of the present invention operates on two cycles of operation, the freezing cycle and the harvest cycle. During the freezing cycle, the compressor pumps a high pressure gas through pipe 13 and T 14 to the condensor 16, where the gas is condensed into a liquid. The liquid refrigerant flows through the dryer 17 and the strainer 20 to the capillary tube 21. The capillary tube controls the rate of flow of liquid refrigerant to the evaporator 22. The liquid refrigerant enters the evaporator 22 .and evaporates, thereby absorbing heat and refrigerating the raised buttons on the evaporator coils 23. The low pressure vapor then leaves the evaporator, and enters the accumulator 24, and from the accumulator travels back to the compressor.

During the harvest cycle, the hot gas solenoid 26 is energized, thereby allowing the high pressure hot refrigerant gas to bypass the condensor 16 and enter the evaporator 22. The hot gas heats the raised buttons of the evaporator coils 23, thereby causing any ice accumulated on the plates and 46 to drop off. The hot gas from the evaporator then returns to the accumulator 24 and from there to the compressor 10.

Water enters the water storage pan 53 from the water source 50 through pipe 51 and the float valve 52. The water pump 54 pumps water from the pan 53 through the water line 55 to the water header 56. The water from the water header 56 runs into the water distributor 57 and out the plurality of apertures 58 in the bottom of the distributor 57. The water flowing through apertures 58 flows over the water bafiles 60, and is directed to run down the surfaces of the plates 45 and 46. The water which passes over the refrigerated spots on the surfaces 45 and 46 freezes, and ice grows on the refrigerated spots. If the water, or freezing cycle is allowed to continue for a sufficient time, the ice which forms on the opposed spots of the surfaces 45 and 46 will grow to a size that the two separate ice particles join together to form a single, spool-shaped ice particle. When the hot gas solenoid 26 is energized, and the evaporator 22 is defrosted, as explained previously, the ice particles drop off of the surfaces 45 and 46 and are directed by the inclined screen 61 to the ice collection bin 62. The water that runs off of the surfaces 45 and 46 passes through the screen 61 back to the water bin 53.

It is to be understood that while we have shown a specific embodiment of our invention, that this is for the purpose of illustration only, and that our invention is to be limited solely by the scope of the appended claims.

We claim as our invention:

1. An ice making machine comprising:

(a) a unitary, seamless metal tube having a horizontal axis;

(b) said metal tube having opposed first and second generally flat walls;

(0) at least one of said walls formed to provide a plurality of raised buttons;

(d) said plurality of raised buttons being spaced along said tube in the direction of the longitudinal axis thereof;

'(e) surface means contacting the raised buttons of said metal tube;

(f) means connected to said metal tube to supply refrigerant thereto to refrigerate the areas of the surface means contacting said raised buttons; and

(g) means for causing water to flow over said surface means to form ice thereon.

2. An ice making machine in accordance with claim 1 wherein both said first and second walls of said metal tube are formed to provide a plurality of raised buttons.

3. An ice making machine in accordance with claim 1 wherein said surface means comprises a stainless steel plate attached to the raised buttons of said metal tube.

References Cited UNITED STATES PATENTS 1,958,734 5/1934 Betts 177 X 2,145,773 l/1939 Mufily 62342 2,506,120 5/1950 Turner 165-177 X 2,775,096 12/1956 Ashley 62347 2,866,322 12/1958 Mufily 62--348 X 3,253,424 5/1966 Van Steenburgh 62347 X WILLIAM J. WYE, Primary Examiner.

MEYER PERLIN, ROBERT A. OLEARY, Examiners.

W. E. WAYNER, Assistant Examiner. 

1. AN ICE MAKING MACHINE COMPRISING: (A) A UNITARY, SEAMLESS METAL TUBE HAVING A HORIZONTAL AXIS; (B) SAID METAL TUBE HAVING OPPOSED FIRST AND SECOND GENERALLY FLAT WALLS; (C) AT LEAST ONE OF SAID WALLS FORMED TO PROVIDE A PLURALITY OF RAISED BUTTONS; (D) SAID PLURALITY OF RAISED BUTTONS BEING SPACED ALONG SAID TUBE IN THE DIRECTION OF THE LONGITUDINAL AXIS THEREOF; (E) SURFACE MEANS CONTACTING THE RAISED BUTTONS OF SAID METAL TUBE; 